1. Field of the Invention
This invention relates to the field of communications controllers and more particularly to the field of such controllers which are activated with a user's tongue.
2. Previous Art
A significant portion of persons who do not have the use of their limbs are isolated from daily functioning in society. Some of these persons may have suffered traumatic injuries to their spinal cord, such as during automobile accidents or sport injuries and the like; others may have had diseases of the neuromuscular and central nervous system. In these types of diseases, cognitive function most often remains intact. It has been found that often these pathologies do not affect the function of the user's tongue. The tongue remains accessible as a communications link after all limb control has been lost, even in such progressive neuromuscular diseases, such as multiple sclerosis.
The number of such disabled people is increasing in the general population. Thus, there is an increased need for new devices that allow the disabled person to work and to have a near-normal lifestyle. With a faster and more aesthetically acceptable communications controller, it is possible for the disabled person to become a productive part of society. There has been a great amount of recent development in this area, particularly in the area of computer controllers for operating mechanical devices.
Current devices exist for hands free computer input. These devices include a mouth stick controller which is a device clenched in the user's teeth and operated by gross head motions to perform various mechanical tasks. This device is utilized primarily by high level quadriplegics and can be wielded with adequate proficiency after some practice. However it requires a high degree of mobility to accomplish specific tasks and is often awkward to use and leads easily to deteriorization of teeth and oral occlusion. Additionally, a mouth stick controller has the limitation that the patient must be in extremely close proximity, in fact a mouth stick controller extends from the mouth to the device being operated.
Voice recognition systems are known. However, further refinement is necessary to produce a reliable method of data communication even for a person having an unimpaired voice. In many cases, quadriplegics have partial paralysis of the diaphragm and larynx. Their speech articulation and volume are severely hampered. Therefore, voice recognition systems, which require good articulation and volume, are not well suited to a broad range of physically impaired persons. Additionally, voice recognition systems present difficulty in environments where multiple users coexist.
Other devices proposed to assist the disabled person include many forms of single switch computer control. This type of control is slow to operate and requires many levels of programming. Typically, a single switch actuation device requires an action such as "sip" and "puff" breathing, eyebrow motion, or chin movements to control or to operate a computer, to actuate an environmental control or to achieve personal mobility. Disabled persons with a great degree of mobility and who have a capacity to operate more than one switch desire increased and faster access to a computer. Currently, single switch driven software does not achieve the desired speed that can be obtained by multiple switch inputs.
Another relevant device is an ultra-sonic head controller. This device is limited to the user that is able to produce at least small and precise head movements necessary for keying a computer via ultra-sonic position detectors. The computer recognizes the position of the head and deviations in head positions are interpreted as an analog signal. An example of an ultrasonic device is the Personics View Control System (VCS), which is currently commercially available. The Personics system includes three ultra sonic transducers housed in a headset to receive a signal transmitted from a control unit. By comparing the signal received at three points on the headset, changes in the angle and rotation of the head are tracked.
Yet another device which is designed for persons of limited mobility is an eye switch apparatus which is an infrared emitter and detector pair mounted on standard eye-glasses. This system operates by emitting small, low power, infrared beams. The reflectivity of the surfaces in front of the emitter can be sensed. For example, when the eyelid opens or closes, an electronics unit activates a relay which serves as a switch. Virtually any body surface can reflect the beam, giving a wide range of threshold levels and possible methods of operation. However, there is a distinct lack of speed in the use of such a device and there is the disadvantage of triggering this type of device unintentionally, such as during normal eye blinking.
The devices currently known are quite limited in the variety of devices they can control. Additionally, presently known devices require physical movements from the disabled user that may not be possible. What is needed is a device which can be used by a large number of persons having limited mobility and which can operate a broad range of devices. The device must not require difficult physical movements for persons suffering from progressive neuromuscular disorders and quadriplegia due to spinal injuries and the device should be aesthetically pleasing.
Low power frequency modulated (FM) radio transmitters are well known in the field of system application controllers and in the communications field. For example, residential wireless telephones, garage door openers, remote controlled toys and various games are applications of frequency modulated radio transmitters to control applications in and around the home.
Presently, miniaturization allows the same FM technology which is used in the home to be used in an intra-oral transmitter intended to help the disabled. However, some difficulties remain. Included in these difficulties are: (1) the need to use carrier frequencies of approximately 88 Mhz to reduce the size of the electric field antenna; (2) the need to continuously transmit the carrier frequency; and (3) limitations on the size of the battery imposed by the small size of these devices. Problems (1) and (2), above, result in excessive battery drain, while problem (3) places a limit on battery life.
The existing devices do not employ some means of communicating to the user the fact that battery output is marginal. This combination of high battery drain and non-reporting of battery status creates a reliability problem. At least one device uses a circuit which turns off the carrier frequency and resets the logic circuits when no user operable switch is activated. But this circuit still requires power to perform its function and thus battery drain remains a major problem.
The use of high frequency, electric field transmission also creates an additional problem: interference between other users who are in the immediate vicinity (20 to 1000 feet). Some applications embed an ID code in every transmission to protect against such interference. This approach increases the battery drain, and lacks a practical method of changing the ID code to prevent interference from a user having the same code.